1. Field of the Invention
The present invention relates generally to hydraulic couplings used in undersea drilling and production applications. More particularly, the invention involves an undersea hydraulic coupling member with a poppet valve having a guide for the valve actuator that opens the poppet valve when it is connected with the opposing coupling member.
2. Description of Related Art
Subsea hydraulic couplings are old in the art. The couplings generally consist of a male member and a female member, with soft seals positioned within the female member to seal the junction between the male and female members. The female member is generally a cylindrical body with a relatively large diameter longitudinal bore at one end and a relatively small diameter longitudinal bore at the other. The small bore facilitates connections to hydaulic lines, while the large bore contains soft seals and receives the male portion of the coupling. The male member includes a cylindrical portion, or probe, at one end having a diameter approximately equal to the diameter of the large bore of the female portion of the coupling. The male member also includes a connection at its other end to facilitate connection to hydraulic lines. When the cylindrical portion of the male member is inserted into the large bore of the female member, according to the various embodiments of the device, the soft seals, or O-rings, either abut the end or face of the male member or engage the cylindrical probe wall about its outer circumference. The hydraulic fluid is then free to flow through the female and male members of the coupling and seals prevent that flow from escaping about the joint and the coupling.
Poppet valves may be installed in the female member and in the male member of the coupling. Each poppet value closes when the coupling is broken so as to prevent fluid from leaking out of the system of which the coupling is a part. Springs or other bias means have been used to urge the poppet valves into the normally closed position.
In recent years, one or more pressure energized metal seals have been used in undersea hydraulic couplings of the foregoing type. For example, in U.S. Pat. No. 4,694,859, to Robert E. Smith III, assigned to National Coupling Company, Inc. of Stafford, Tex., an undersea hydraulic coupling and metal seal is disclosed. A reusable metal seal engages the outer circumference of the male member probe when it is positioned within the female member bore. The metal seal is held in place by a retainer. The male and female members each have valve actuators extending from the poppet valves. When the male member enters the female member bore and the valve actuators are engaged, each of the poppet valves is urged open and the poppet valve springs are compressed. U.S. Pat. No. 5,762,106 to Robert E. Smith III, assigned to National Coupling Company, Inc. also shows an undersea hydraulic coupling and radial metal seal that engages the diameter of the probe or male member.
In subsea hydraulic systems of the foregoing type, it is desirable to increase flow rates through the system of which the couplings are a part. The flow rate through the couplings, and the hydraulic lines attached to the couplings, are a function of the diameter of the internal bore through each coupling and line. As known by those skilled in the art, the maximum flow rate coefficient through a coupling may be determined and calculated based on the dimensions of the coupling bore.
To withstand the higher pressures of increased hydraulic flow through a coupling, the body of the coupling member, and the probe section of the male member in particular, must be of sufficient thickness to withstand the internal working pressure and the pressure external to the coupling at substantial ocean depths. However, it is undesirable to increase the size and thickness of the coupling to accommodate higher working pressures and higher subsea pressures. Remote operating vehicles (ROVs) must frequently be used to transport and engage and disengage coupling members. The ROVs may be limited in weight and size capacity to transport and install coupling members. Frequently, multiple coupling members are connected to a manifold plate and must be transported while subsea with couplings attached to an opposing manifold plate.
For the above reasons, attempts have been made to increase the flow rate through couplings, and at the same time to reduce the size and weight of the couplings. Couplings have been proposed having reduced diameters and extended male member probe sections. Poppet valves used in couplings of the foregoing type generally are positioned in the probe section and include a valve actuator extending from the apex of the conical valve face. The valve actuator of the male member engages the valve actuator of the female member to urge the poppet valves open and establish fluid flow through the coupling. In couplings with reduced diameters and extended male member probe sections, it also may be necessary to increase and extend the length of the actuator in one or both coupling members.
For example, U.S. patent application Ser. No. 09/293,554 to Robert E. Smith III, assigned to National Coupling Company, Inc. relates to an undersea hydraulic coupling having an extended probe section with a valve spring having a greater diameter than the diameter of the extended probe section. The larger spring helps provide sufficient forces to prevent the poppet valve of the male member from opening at high subsea pressures, while the extended probe section has a smaller diameter to minimize the required sealing surface. The poppet valve has a valve actuator extending therefrom through the extended probe section. However, forces including impact forces (i.e., collisions with other coupling members, equipment, or debris) and hydraulic forces (i.e., hydraulic fluid or seawater) may cause deflection, bending or other damage to the valve actuator when the coupling members are connected, disconnected or in use.
Alternatively, the actuators of poppet valves used in certain other hydraulic couplings have been extended through the probe section of the coupling for other reasons.
For example, U.S. Pat. Nos. 5,099,882 and 5,203,374 to Robert E. Smith III, assigned to National Coupling Company, Inc., show poppet valve actuators extending through the probe section of the male coupling member of pressure balanced undersea hydraulic couplings. In these patents, a flange on the poppet valve actuator is shown. The flange acts as a stop that abuts a shoulder in the bore which accommodates the valve actuator, and acts as a stop to prevent the actuator from blowing out of the coupling bore due to pressure.
It is desirable to include extended poppet valve actuators in one or both coupling members, but it is difficult to ensure alignment of the poppet valve actuator in the bore or cavity of the coupling member through which the poppet valve actuator extends. The actuator may become misaligned due to mechanical forces that would damage the actuator, and/or the pressure of hydraulic fluid, sea water, or other ocean debris impacting the actuator. Accordingly, an improved valve actuator is needed that will ensure alignment of the actuator and provide for smooth flow through the coupling members. Additionally, an improved poppet valve actuator is needed to allow the poppet valve to be precisely guided when the coupling members are connected together at substantial ocean depths. Moreover, an improved poppet valve actuator is needed that will help increase flow of hydraulic fluid through the bore in which the actuator is positioned in the coupling member.
The present invention resides in an undersea hydraulic coupling of the foregoing type including a male member, or probe, having a poppet valve with a guide on the valve actuator to ensure alignment of the actuator in the coupling member. The guide includes a plurality of ports, such as holes, grooves, or slots therethrough to allow hydraulic fluid to maintain a high flow rate through the annulus between the actuator and bore where it is positioned. The guide allows the poppet valve to be precisely guided in the male member probe section when the probe is connected to or disconnected from the female coupling member. The guide may be integral with the poppet actuator or, alternatively, may be a sleeve around the actuator or attached to the bore of the coupling member through which the actuator moves. The present invention allows increased flow of hydraulic fluid through the coupling member having an extended or lengthened poppet valve actuator.